1. Field
The present application relates to an image processing device and an image processing method which correct, for an image captured by a digital camera or the like, aberration that varies depending on an image height such as distortion or chromatic aberration of magnification.
2. Description of the Related Art
A light receiving surface of a two-dimensional image sensor mounted on a digital camera or a color image scanner has arranged therein filters of three colors corresponding to the three primary colors of light, according to the arrangement of pixels in the image sensor. An electrical signal, reflecting the strength of light of the component that transmitted through these color filters, is acquired in each pixel.
In a general two-dimensional image sensor, square pixels are arranged as a two-dimensional array, and color filters corresponding to each of the R, G, and B components are arranged according to the Bayer array. In the Bayer array, filters that transmit light with a wavelength corresponding to the G component reflecting the brightness are successively arranged in a diagonal direction, whereas filters that transmit light with wavelengths corresponding to the R and B components are arranged in every other rows and columns, respectively.
With an image sensor having color filters arranged therein according to the above-mentioned Bayer array, only the strength of the component corresponding to the transmission wavelength of the color filter corresponding to the pixel data of each pixel is indicated. Therefore, the color at the position of each pixel of the image formed on the image sensor is obtained by interpolating the surrounding pixel data for each of the R, G, and B components.
The interpolation process of obtaining, from a Bayer image acquired by the image sensor having color filters of the Bayer array, image data having all the R, G, and B components indicating the color at the position of each pixel is referred to as a deBayer process.
Conventionally, in most cases where a Bayer image is acquired by a two-dimensional image sensor, the above-mentioned deBayer process is first performed to obtain image data having all the R, G, and B components for each pixel, and thereafter a variety of image processes such as correcting distortion or chromatic aberration of magnification are performed (See Patent Document 1: Japanese Patent No. 3549413).
Here, when performing correction of distortion and chromatic aberration of magnification for the image data after the deBayer process, the amount of computation becomes enormous because position calculation and interpolation for the correcting process are performed for each of the R, G, and B components in image data of a whole frame.
A technique described in the Patent Document 1 calculates the amount of correction for the R and B components at the position of interest by adding the component of chromatic aberration of magnification for the R and B components to the component of the distortion obtained for the G component at the image height corresponding to the position of each pixel. However, in such a process, the merit of performing the aberration correcting process at the Bayer image stage cannot be fully utilized. That is, simple application of the technique described in the Patent Document 1 requires, also in the position calculation for the R pixels and B pixels, calculation of the amount of distortion for the G component at these pixel positions.